Laminate acoustic panel

ABSTRACT

Described herein is a laminate acoustic panel comprising a first layer and a second layer, as well as a ceiling system that includes the laminate acoustic panel.

FIELD OF INVENTION

Embodiments of the present invention relate to laminate acoustic ceilingpanels, methods for preparing laminate acoustic ceiling panels, andceiling systems comprising the laminate acoustic ceiling panels.

BACKGROUND

Various types of ceiling systems have been used in commercial andresidential building construction to provide the desired acousticalperformance. Noise blocking between rooms is required for a variety ofpurposes, including speech privacy as well as not bothering theoccupants of adjacent rooms. Sound dampening within a single room isalso required for a variety of purposes, including decreasing volumelevels within a single space.

Previous attempts have been made to improve noise blocking betweenadjacent rooms. However, such previous attempts have either beendirected to single layered structures or laminate-structures havinglayers that are bonded together across substantially the entireinterface of layers. Such previous attempts fail to address how theinterface between layers impacts both noise blocking and sound dampeningcharacteristics of the acoustic ceiling panels. Thus, there is a needfor a new laminate acoustic ceiling panel having an interface that canenhances the desired acoustical properties.

SUMMARY

According to some embodiments, the present invention is directed to anacoustic ceiling panel comprising a laminate structure having a firstlayer and a second layer. The first layer comprises a first majorsurface and a second major surface. The second major surface of thefirst layer is defined by a perimeter. The second major surface of thefirst layer comprises a perimeter region adjacent the perimeter of thesecond major surface of the first layer. The second major surfacefurther comprises a central region circumscribed by the perimeter regionof the second major surface of the first layer. The second layercomprises a first major surface and a second major surface. The firstmajor surface of the second layer is defined by a perimeter. The firstmajor surface of the second layer comprises a perimeter region adjacentthe perimeter of the first major surface of the second layer. The firstmajor surface of the second layer further comprises a central regioncircumscribed by the perimeter region of the first major surface of thesecond layer. The second major surface of the first layer is coupled tothe first major surface of the second layer by an adhesive applied to atleast one of the perimeter region of the second major surface of thefirst layer or the perimeter region of the first major surface of thesecond layer. The central region of the second major surface of thefirst layer and the central region of the first major surface of thesecond layer being are each free of adhesive.

According to other embodiments, the present invention is directed to anacoustic ceiling panel comprising a laminate structure having a firstlayer and a second layer. The first layer comprises a first majorsurface and a second major surface. The second major surface of thefirst layer is defined by a perimeter. The second major surface of thefirst layer comprises a perimeter region adjacent the perimeter of thesecond major surface of the first layer. The second major surface of thefirst layer further comprises a central region circumscribed by theperimeter region of the second major surface of the first layer. Thesecond layer comprises a first major surface and a second major surface.The first major surface of the second layer is defined by a perimeter.The first major surface of the second layer comprises a perimeter regionadjacent the perimeter of the first major surface of the second layer.The first major surface of the second layer further comprises and acentral region circumscribed by the perimeter region of the first majorsurface of the second layer. The second major surface of the first layeris coupled to the first major surface of the second layer by a pluralityof adhesive strips applied to at least one of the perimeter region ofthe second major surface of the first layer or the perimeter region ofthe first major surface of the second layer. The plurality of adhesivestrips collectively forming a closed-geometry that circumscribes thecentral region of the second major surface of the first layer and thecentral region of the first major surface of the second layer.

In other embodiments, the present invention is directed to an acousticceiling panel comprising a first layer and a second layer. The firstlayer comprises a first major surface, a second major surface, and aside surface extending between the first and second major surfaces ofthe first layer. The side surface of the first layer intersects thesecond major surface of the first layer to form an upper edge of thefirst layer. The upper edge of the first layer forms a perimeter of thesecond major surface. The second major surface comprises a perimeterregion adjacent the perimeter and a central region circumscribed by theperimeter region. The upper edge of the first layer comprises a firstupper edge portion, a second upper edge portion, a third upper edgeportion, and a fourth upper edge portion. The second upper edge portionis opposite the first upper edge portion. The third upper edge portionextends between the first and second upper edge portions. The fourthupper edge portion is opposite the third upper edge portion and extendsbetween the first and second upper edge portions. The second layercomprises a first major surface, a second major surface, and a sidesurface extending between the first and second major surfaces of thesecond layer. The second major surface of the first layer coupled to thefirst major surface of the second layer by at least a first adhesivestrip, a second adhesive strip, a third adhesive strip, and a fourthadhesive strip. The first adhesive strip extends adjacent to andsubstantially parallel to the first edge portion. The second adhesivestrip extends adjacent to and substantially parallel to the second edgeportion. The third adhesive strip extends adjacent to and substantiallyparallel to the third edge portion. The fourth adhesive strip extendingadjacent to and substantially parallel to the fourth edge portion.

According to some embodiments, the preset invention is directed to asuspended ceiling system comprising a ceiling grid, a plenary space, aroom environment, and at least one acoustic ceiling panel according tothe present invention. The ceiling grid may comprise a plurality offirst members and a plurality of second members, the first and secondmembers intersecting at a substantially perpendicular angle defining aplurality of grid openings. The plenary space is above the ceiling grid.The room environment is below the ceiling grid. The at least oneacoustic ceiling panels according to the present invention rests in oneof the plurality of grid openings of the ceiling grid.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the exemplary embodiments of the present invention willbe described with reference to the following drawings, where likeelements are labeled similarly, and in which:

FIG. 1 is a perspective view of the ceiling system according to thepresent disclosure;

FIG. 2 is a side profile view of a portion of the ceiling system 1according to the present disclosure;

FIG. 3 is a perspective view of the ceiling panel according to thepresent disclosure;

FIG. 4 is a side view of the ceiling panel according to the presentdisclosure;

FIG. 5 is a cross-sectional view of the ceiling panel according to thepresent disclosure along line IV of FIG. 3;

FIG. 6 is a perspective view of the first layer and the second layer ofthe ceiling panel according to the present disclosure, wherein the firstand second layer are separated;

FIG. 7 is a top view of the first layer, showing the second majorsurface of the first layer according to one embodiment of the presentdisclosure;

FIG. 8 is a top view of the first layer, showing the second majorsurface of the first layer according to another embodiment of thepresent disclosure;

FIG. 9 is a top view of the first layer, showing the second majorsurface of the first layer according to another embodiment of thepresent disclosure;

FIG. 10 is a top view of the first layer, showing the second majorsurface of the first layer according to another embodiment of thepresent disclosure; and

FIG. 11 is a bottom view of the second layer, showing the first majorsurface of the second layer according to another embodiment of thepresent disclosure.

All drawings are schematic and not necessarily to scale. Parts given areference numerical designation in one figure may be considered to bethe same parts where they appear in other figures without a numericaldesignation for brevity unless specifically labeled with a differentpart number and described herein.

DETAILED DESCRIPTION

As shown in FIGS. 1 and 2, the present invention is directed to aceiling system 1 comprising a ceiling grid 5 and at least one acousticceiling panel 20. A plenary space 2 may exist above the ceiling grid 5.The plenary space 2 is the space that exists above the acoustic ceilingpanels 20 and above the ceiling grid 5 and below a roof or a subfloor 4of an above adjacent floor in a building. The plenary space 2 providesroom for mechanical lines to be run throughout a building—e.g. HVAC,plumbing, data lines, etc. A room environment 3 may exist below theacoustic ceiling panels 20 and below the ceiling grid 5. The roomenvironment 3 is the space occupied by inhabitants of a room—e.g. roomenvironments 3 in an office building would be the space occupied bydesks, office workers, computers, etc. The combination of the ceilinggrid 5 and the acoustic ceiling panels 20 may act as an acoustic andaesthetic barrier between the room environment 3 and the plenary space2, as well as a sound deadening layer for noise that exists within theroom environment 3, as discussed herein.

The ceiling grid 5 may comprise a plurality of first members 6 extendingparallel to each other. In some embodiments, the ceiling grid 5 mayfurther comprise a plurality of second members 7 that extend parallel toeach other. The plurality of first members 6 may intersect the pluralityof second members 7 to form a grid pattern having a plurality of gridopenings 8. In some embodiments, the plurality of first members 6intersects the plurality of second members 7 at a substantiallyperpendicular angle, thereby forming rectangular grid openings 8. Therectangular grid openings 8 may be square or any other shape that isesthetical or functional.

As shown in FIG. 2, each of the plurality of first members 6 and each ofthe plurality of second members 7 may comprises T-bars having ahorizontal flange 10 and a web 11. The plenary space 2 exists above theT-bars and the room environment 3 exists below the T-bars.

The ceiling system 1 of the present disclosure comprises at least oneacoustic ceiling panel 20 that is mounted to the ceiling grid 5 withinone of the plurality of grid openings 8. The ceiling system 1 maycomprises a plurality of acoustic ceiling panels 20 mounted to theceiling grid 5, each of the plurality of acoustic ceiling panels 20resting within one of the plurality of grid openings 8. In someembodiments, something other than the acoustic ceiling panel 20 (forexample, light fixture or an air duct vent) may be mounted to theceiling grid 5 within at least one of the grid openings 8 (notpictured).

As demonstrated by FIGS. 3-6, the acoustic ceiling panel 20 may comprisea first layer 100 and a second layer 200. In some embodiments of thepresent invention, the acoustic ceiling panel 20 may further comprise ascrim 300. As demonstrated by FIG. 2, the acoustic ceiling panel 20 maybe mounted on the ceiling grid 5 of the ceiling system 1 so that thefirst layer 100 of the acoustic ceiling panel 20 is adjacent to the roomenvironment 3 and the second layer 200 is adjacent to the plenary space2.

As shown by FIGS. 4-6, the first layer 100 of the acoustic ceiling panel20 comprises a first major surface 101 and a second major surface 102.The first layer 100 further comprises a side surface 103 extendingbetween the first major surface 101 and the second major surface 102.The side surface 103 of the first layer 100 intersects the first majorsurface 101 of the first layer 100 to form a lower edge 107 of the firstlayer 100. The side surface 103 of the first layer 100 intersects thesecond major surface 102 of the first layer 100 to form an upper edge104 of the first layer 100.

In some embodiments of the present invention, the side surface 103 ofthe first layer 100 may comprise a stepped profile having an upper sidesurface 103 b and a lower side surface 103 a. The lower side surface 103a of the first layer 100 intersects the first major surface 101 of thefirst layer 100 to form the lower edge 107 of the first layer 100. Theupper side surface 103 b of the first layer 100 intersects the secondmajor surface 102 of the first layer 100 to form the upper edge 104.

An intermediate surface 108 extends between the lower side surface 103 aand the upper side surface 103 b in a direction that is substantiallyperpendicular to the side surface 103, the upper side surface 103 a, andthe lower side surface 103 b of the first layer 100. In someembodiments, the intermediate surface 108 faces the same direction asthe first major surface 101 of the first layer 100. In otherembodiments, the intermediate surface 108 faces a direction oblique tothe first major surface 101.

The stepped profile comprises the combination of the upper side surface103 b, the intermediate surface 108, and the lower side surface 103 a.According to this embodiment, the second major surface 102 of the firstlayer 100 has an area that is greater than an area of the first majorsurface 101 of the first layer 100. In some embodiments the surface areaof the second major surface 102 of the first layer 100 is equal to thesum of the area of the first major surface 102 and the area of theintermediate surface 108 of the first layer 100. As shown in FIG. 2,after the acoustic ceiling panel 20 have been mounted to the ceilinggrid 5, the intermediate surface 108 of the first layer 100 may abut atleast a portion of a top surface of the horizontal flange 10 of at leastone of the first member 6 or the second member 7 of the ceiling grid 5.The abutment between the intermediate surface 108 of the first layer 100and the top surface of the horizontal flange 10 allows the acousticalceiling panel 10 to rest in a fully installed position

As shown in FIGS. 6-10, the upper edge 104 of the first layer 100 formsa perimeter of the second major surface 102 of the first layer 100. Thesecond major surface 102 comprises a perimeter region 105 that isadjacent to both the upper edge 104 of the first layer 100 and theperimeter of the second major surface 102. The second major surface 102of the first layer 100 may further comprise a central region 106 that iscircumscribed by the perimeter region 105 of the second major surface102 of the first layer 100. FIGS. 6-10 show non-limiting embodiments ofa dotted boundary 170 between the central region 106 and the perimeterregion 105 of the first layer 100. In FIGS. 6-10, the dotted boundary170 is rectangular; however, the present invention does not limit theshape of the dotted boundary 170 to any particular shape (e.g., polygon,circle, ellipsis, non-geometric shapes, etc.).

The upper edge 104 of the first layer 100 comprises a first upper edgeportion 120, a second upper edge portion 121, a third upper edge portion122, and a fourth upper edge portion 123. The second upper edge portion121 is opposite the first upper edge portion 120, and the fourth upperedge portion 123 is opposite the third upper edge portion 122. The thirdupper edge portion 122 extends between the first upper edge portion 120and the second upper edge portion 121. The fourth upper edge portion 123extends between the first upper edge portion 120 and the second upperedge portion 121.

In some embodiments, the third upper edge portion 122 extendsperpendicular to both of the first upper edge portion 120 and the secondupper edge portion 121. In some embodiments, the fourth upper edgeportion 123 extends substantially perpendicular to both of the firstupper edge portion 120 and the second upper edge portion 121. In someembodiments the first upper edge portion 120 extends substantiallyparallel to the second upper edge portion 121.

In some embodiments, the stepped profile of the first layer 100 may bepresent on each of the side surfaces 103 of the first layer 100. Inother embodiments, the stepped profile may only be present on twoopposite side surfaces 103 of the first layer 100. For example, the sidesurfaces 103 of the first layer 100 that form the first upper edgeportion 120 and the second upper edge portion 121 may comprise a steppedprofile while the side surfaces 103 of the first layer 100 that form thethird upper edge portion 122 and the fourth upper edge portion 123 donot comprise a stepped profile. In a preferred embodiment, the firstlayer 100 is closer to the sound source, e.g., the room environment 3.

In some embodiments, the first layer 100 may be comprised of fiberglass,mineral wool (such as rock wool, slag wool, or a combination thereof),synthetic polymers (such as melamine foam, polyurethane foam, or acombination thereof), mineral cotton, silicate cotton, or combinationsthereof. In some embodiments the first layer 100 is produced fromfiberglass. In some embodiments the first layer 100 predominantlyprovides a sound absorption function and preferred materials forproviding the sound absorption function for the first layer 100 includefiberglass The first layer provides a ceiling NRC rating of 0.7 orgreater, preferably 0.9 or greater. NRC (Noise Reduction Coefficient) isfurther described below. In some non-limiting embodiments of the presentdisclosure, the first layer may be selected from the Optima™ and Lyra™fiberglass panel lines produced by Armstrong (Armstrong WorldIndustries, Inc.)—for example, Lyra 8372 or Optima 3251.

As demonstrated by FIGS. 3-6, the second layer 200 comprises a firstmajor surface 201 and a second major surface 202. The second layer 200may further comprise a side surface 203 extending between the firstmajor surface 201 of the second layer 200 and the second major surface202 of the second layer 200. The side surface 203 of the second layer200 intersects the second major surface 202 of the second layer 200 toform an upper edge 204 of the second layer 200. The side surface 203 ofthe second layer 200 intersects the first major surface 201 of thesecond layer 200 to form a lower edge 207 of the second layer 200.

As shown in FIGS. 3 and 6, the upper edge 204 of the second layer 200forms a perimeter of the second major surface 202 of the second layer200. As demonstrated in FIG. 11, the lower edge 207 of the second layer200 forms a perimeter of the first major surface 201 of the second layer200. The lower edge 207 of the second layer 200 comprises a first loweredge portion 220, a second lower edge portion 221, a third lower edgeportion 222, and a fourth lower edge portion 223. The second lower edgeportion 221 is opposite the first lower edge portion 220, and the fourthlower edge portion 223 is opposite the third lower edge portion 222. Thethird lower edge portion 222 extends between the first lower edgeportion 220 and the second lower edge portion 221. The fourth lower edgeportion 223 extends between the first lower edge portion 220 and thesecond lower edge portion 221.

As shown in FIGS. 4-6, the side surface 203 of the second layer 200 mayfurther comprise an upper side surface 203 b and a lower side surface203 a. The upper side surface 203 b of the second layer 200 intersectswith the second major surface 202 of the second layer 200 forming theupper edge 204 of the second layer 200. The lower side surface 203 a ofthe second layer 200 intersects with the first major surface 201 of thesecond layer 200 forming the lower edge 207 of the second layer 200.

In some embodiments the upper side surface 203 b of the second layer 200is coplanar with the lower side surface 203 a of the second layer200—such that the area of the second major surface 202 of the secondlayer 200 is equal to the area of the first major surface 201 of thesecond layer. In some embodiments, the upper side surface 203 b of thesecond layer 200 is beveled inward at an angle of 30, 45, or 60 degreeangle relative to lower side surface 203 a of the second layer—such thatthe area of the second major surface 202 of the second layer 200 is lessthan the area of the first major surface 201 of the second layer. In apreferred embodiment, the second layer 200 is away from the soundsource, e.g., facing toward the plenary space 2.

In some embodiments the second layer 200 may comprise fiberglass,mineral wool (such as rock wool, slag wool, or a combination thereof),synthetic polymers (such as melamine foam, polyurethane foam, or acombination thereof), mineral cotton, silicate cotton, gypsum, orcombinations thereof. In some embodiments the second layer 200 isproduced from mineral wool. In some embodiments, the second layer 200predominantly provides a sound attenuation function and preferredmaterials for providing the sound attenuation function for the secondlayer 200 include mineral wool. The second layer 200 provides a ceilingCAC rating of at least 35, preferably at least 40. CAC (CeilingAttenuation Class) is further described below. In some non-limitingembodiments of the present disclosure, the second layer may be selectedfrom the School Zone™ and Calla™ panel lines produced by Armstrong—forexample, School Zone 1810.

As shown in FIG. 5, the acoustic ceiling panel 20 is formed bypositioning the first major surface 201 of the second layer 200 adjacentto the second major surface 102 of the first layer 100, thereby creatingan interface between the first layer 100 and the second layer 200.Specifically, the interface exists between the first major surface 201of the second layer 200 and the second major surface 102 of the firstlayer 100.

The first layer 100 may be attached to the second layer 200 with anadhesive 50. Specifically, the second major surface 102 of the firstlayer 100 may be coupled to the first major surface 201 of the secondlayer 200 by the adhesive 50 to create a cohesively adhere the first andsecond layers 100, 200 to form a cohesive multilayer laminate. Thesecond major surface 102 of the first layer 100 may be coupled to thefirst major surface 201 of the second layer 200 by the adhesive 50 sothat the perimeter and the upper edge 104 of the first layer 100 isaligned with the perimeter and the lower edge 207 of the second layer200. In other embodiments, the first layer 100 may be attached to thesecond layer 200 by mechanical coupling.

In some embodiments, the second major surface 102 of the first layer 100and the first major surface 201 of the second layer 200 may be coupledby the adhesive 50 so that the first upper edge 120 of the first layer100 is aligned with the first lower edge 220 of the second layer 200;the second upper edge 121 of the first layer 100 is aligned with thesecond lower edge 221 of the second layer 200; the third upper edge 122of the first layer 100 is aligned with the fourth lower edge 223 of thesecond layer 200; and the fourth upper edge 123 of the first layer 100is aligned with third lower edge 222 of the second layer 200.

In some embodiments, the first layer 100 and the second layer 200 may becoupled so that the perimeter and the upper edge 104 of the first layer100 is not aligned with the perimeter and the lower edge 207 of thesecond layer 200 (not pictured). Specifically, the first upper edge 120of the first layer 100 may extend oblique to the first lower edge 220 ofthe second layer 200. The second upper edge 121 of the first layer 100may extend oblique to the second lower edge 221 of the second layer 200.The third upper edge 122 of the first layer 100 may extend oblique tothe fourth lower edge 223 of the second layer 200. The fourth upper edge123 of the first layer 100 may extends oblique to the third lower edge222 of the second layer 200.

According to another embodiment of the present disclosure, the area ofthe first major surface 201 of the second layer 200 may be larger thanthe area the second major surface 102 of the first layer 100, therebyleaving at least a portion of the first major surface 201 of the secondlayer 200 exposed (not pictured). The exposed portion of the first majorsurface 201 of the second layer 200 creates a step between the sidesurface 103 of the first layer 100 and the side surface 203 of thesecond layer 200. According to this embodiment, the perimeter of thefirst layer 100 is smaller than the perimeter of the second layer 200.The portion of the first major surface 201 of the second layer 200 thatremains exposed by the step between the side surfaces 103, 104 may abuta portion of the top surface of the horizontal flange 10 of the firstand second members 6, 7 after the acoustic ceiling panel 20 is mountedto the ceiling grid 5—similar to the intermediate surface 108 of thefirst layer 100 may abut the horizontal flange 10 of the first andsecond members 6, 7 of the ceiling grid 5. According to this embodiment,the first layer 100 has a side surface 103 that may or may not comprisethe stepped profile of the lower side surface 103 a, intermediatesurface 108, and upper side surface 103 b. In other embodiments, thearea of the first major surface 201 of the second layer 200 may besmaller than the area the second major surface 102 of the first layer100.

Each of the side surfaces 103 of the first layer 100 may extend coplanarto each of the side surfaces 203 of the second layer 200. Specifically,each of the upper edge portions 103 b of the first layer 100 may extendcoplanar to each of the lower edge portions 203 a of the second layer100.

The adhesive 50 may be applied to at least one of the perimeter region105 of the second major surface 102 of the first layer 100 or theperimeter region 205 of the first major surface 201 of the second layer200. The central region 106 of the second major surface 102 of the firstlayer 100 is substantially free of any adhesive 50 that couples thecentral region 106 of the second major surface 102 of the first layer100 to the first major surface 201 of the second layer 200. The centralregion 206 of the first major surface 201 of the second layer 200 issubstantially free of any adhesive that couples the central region 206of the first major surface 201 of the second layer 200 to the secondmajor surface 102 of the first layer 100.

In some embodiments, the central region 106 of the second major surface102 of the first layer 100 is in free floating contact with the firstmajor surface 201 of the second layer 200. In some embodiments, thecentral region 206 of the first major surface 201 of the second layer200 is in free floating contact with the second major surface 102 of thefirst layer 100. The interface between the first major surface 201 ofthe second layer 200 and the second major surface 102 of the first layeris substantially free of adhesive within the central region 106 of thefirst layer 100 and the central region 206 of the second layer.

In some embodiments, the first layer 100 and the second layer 200 arecoupled by mechanical attachment means (e.g., needle bunching, or clips)in addition to or alternatively to the adhesive 50. In some embodiments,the central region 106 of the first layer 100 is not in physical contactwith the central region 206 of the second layer 200.

According to the present invention, the adhesive 50 may be any adhesivethat provides structural integrity to the acoustic ceiling panel 20having the attached first and second layers 100, 200 such that theacoustic ceiling panel 20 can be handled without separating the firstand second layers 100, 200—e.g., even when certain section or sectionsof the acoustic ceiling panel 20 are cut for installation. Suitableadhesives include aqueous adhesives and solvent based adhesives,including adhesives of polyvinyl acetate, urethane, acrylates, andpolyester. The adhesives may be a hot-melt adhesive, pressure sensitiveadhesive, or acoustical adhesive. The adhesive may be applied as dots,continuous strips, or discontinuous strips to one or more of theperimeter regions 105, 205 of the first and second layers 100, 200 ofthe acoustic ceiling panel 20, as discussed further herein.

According to some embodiments of the present disclosure, the adhesive 50applied to at least one of the perimeter region 105 of the second majorsurface 102 of the first layer 100 and the perimeter region 205 of thefirst major surface 201 of the second layer 200 comprises, for example,a plurality of adhesive strips. In other embodiments, the adhesive isapplied in a pattern to minimize the area of contact between the firstand second layers occupied by the applied adhesive. For example, theadhesive is applied as a dot in each of the four corners of theperimeter regions of a rectangular panel.

As shown in FIGS. 6-10, the plurality of adhesive strips may comprise afirst adhesive strip 130, a second adhesive strip 131, a third adhesivestrip 132, a fourth adhesive strip 133. The first adhesive strip 130,the second adhesive strip 131, the third adhesive strip 132, and thefourth adhesive strip 133 may each independently be a continuous or adiscontinuous strip of adhesive. The first adhesive strip 130, thesecond adhesive strip 131, the third adhesive strip 132, and the fourthadhesive strip 133 may each independently be linear or curvilinear.

The first adhesive strip 130 may extend adjacent to the first upper edgeportion 120 of the first layer 100. The second adhesive strip 131 mayextend adjacent to the second upper edge portion 121 of the first layer100. The third adhesive strip 132 may extend adjacent to the third upperedge portion 122 of the first layer 100. The fourth adhesive strip 133may extend adjacent to the fourth upper edge portion 123 of the firstlayer 100. According to this embodiment, the first adhesive strip 130,the second adhesive strip, 131, the third adhesive strip 132, and thefourth adhesive strip 133 may each independently extend to thecorresponding first upper edge portion 120, second upper edge portion121, third upper edge portion 122, and fourth upper edge portion 123 atan oblique or substantially parallel angle.

In non-limiting the embodiments, the first adhesive strip 130 may extendadjacent to the first lower edge portion 220 of the second layer 200.The second adhesive strip 131 may extend adjacent to the second loweredge portion 221 of the second layer 200. The third adhesive strip 132may extend adjacent to the third lower edge portion 222 of the secondlayer 200. The fourth adhesive strip 133 may extend adjacent to thefourth lower edge portion 223 of the second layer 200. According to thisembodiment, the first adhesive strip 130, the second adhesive strip,131, the third adhesive strip 132, and the fourth adhesive strip 133 mayeach independently extend to the corresponding first lower edge portion220, second lower edge portion 221, third lower edge portion 222, andfourth lower edge portion 223 at an oblique or substantially parallelangle.

As shown in FIGS. 7 and 8, the first adhesive strip 130 may be spaced afirst distance D₁ from the first upper edge portion 120 of the firstlayer 100. The second adhesive strip 131 may be spaced a second distanceD₂ from the second upper edge portion 121 of the first layer 100. Thethird adhesive strip 132 may be spaced a third distance D₃ from thethird upper edge portion 122 of the first layer 100. The fourth adhesivestrip 133 may be spaced a fourth distance D₄ from the fourth upper edgeportion 123 of the first layer 100.

In some embodiments the first distance D₁, the second distance D₂, thethird distance D₃, and the fourth distance D₄, each independently rangefrom about ⅛ of an inch to about ⅝ of an inch. In some embodiments, thefirst distance D₁, the second distance D₂, the third distance D₃, andthe fourth distance D₄, each independently range from about ¼ of an inchto about ½ of an inch. In some embodiments, the first distance D₁, thesecond distance D₂, the third distance D₃, and the fourth distance D₄,is about ⅜ of an inch.

The first adhesive strip 130 may be spaced from the dotted boundary 170of the central region 106 by a fifth distance D₅. The second adhesivestrip 131 may be spaced from the dotted boundary 170 of the centralregion 106 by a sixth distance D₆. The third adhesive strip 132 may bespaced from the dotted boundary 170 of the central region 106 by aseventh distance D₇. The fourth adhesive strip 133 may be spaced fromthe dotted boundary 170 of the central region 106 by an eighth distanceDg.

In some embodiments the fifth distance D₅, the sixth distance D₆, theseventh distance D₇, and the eighth distance D₈, each independentlyrange from about 0 inches to about ⅝ of an inch. In some embodiments,the fifth distance D₅, the sixth distance D₆, the seventh distance D₇,and the eighth distance D₈, each independently range from about ⅛ of aninch to about ½ of an inch. In some embodiments, the fifth distance D₅,the sixth distance D₆, the seventh distance D₇, and the eighth distanceD₈ is about 0 inches or about ⅜ of an inch.

According to the embodiments when the fifth distance D₅, the sixthdistance D₆, the seventh distance D₇, and the eighth distance D₈, areindependently 0 inches, the central region 106 is directly circumscribedby at least one of the first adhesive strip 130, the second adhesivestrip 131, the third adhesive strip 132, and the fourth adhesive strip133.

The first adhesive strip 130, the second adhesive strip 131, the thirdadhesive strip 132, and the fourth adhesive strip 132 may each beindependently applied to at least one of the first major surface 201 ofthe second layer 200 or the second major surface 102 of the first layer100 in a width of about ¼ of an inch to about ½ of an inch. The firstadhesive strip 130, the second adhesive strip 131, the third adhesivestrip 132, and the fourth adhesive strip 132 may each be applied to atleast one of the first major surface 201 of the second layer 200 or thesecond major surface 102 of the first layer 100 in a width of about ⅜ ofan inch.

Depending on the width of the first, second, third, and fourth adhesivestrip 130, 131, 132, and 133 and the first, second, third, fourth,fifth, sixth, seventh, and eighth distance D₁, D₂, D₃, D₄, D₅, D₆, D₇,and D₈, the central region 106 of the first layer 100 may occupy betweenabout 70% to about 99% of the surface area of the second major surface102 of the first layer 100—the same surface area percentages apply tothe central region 206 of the second layer 200. In some embodiments, thecentral region 106 of the first layer 100 may occupy between about 85%to about 95%, for example about 95%, of the surface area of the secondmajor surface 102 of the first layer 100—the same surface areapercentages apply to the central region 206 of the second layer 200.

The first adhesive strip 130, the second adhesive strip 131, the thirdadhesive strip 132, and the fourth adhesive strip 132 may each beapplied to at least one of the first major surface 201 of the secondlayer 200 or the second major surface 102 of the first layer 100 in athickness of about 0.01 inches to about 0.25 inches. The first adhesivestrip 130, the second adhesive strip 131, the third adhesive strip 132,and the fourth adhesive strip 132 may each be independently applied toat least one of the first major surface 201 of the second layer 200 orthe second major surface 102 of the first layer 100 in a thickness ofabout 0.03 inches.

In some embodiments, the adhesive 50 is applied to at least one of onthe corners of the perimeter region 105 of the second major surface 102of the first layer 100 or the perimeter region 205 of the first majorsurface 201 of the second layer 200.

The first, second, third, fourth, fifth, sixth, seventh, and eighthdistances D₁, D₂, D₃, D₄, D₅, D₆, D₇, and D₈, described with respect tothe central region 106 of the second major surface 102 of the firstlayer 100 also apply to the central region 206 of the first majorsurface 201 of the second layer 200.

In some embodiments of the present invention, the adhesive 50 is appliedto at least one of the first major surface 201 of the second layer 200or the second major surface 102 of the first layer 100 such that a totalof about 10 g to about 30 g of adhesive 50 exists in the acousticceiling panel 20. In some embodiments of the present invention, theadhesive 50 is applied to at least one of the first major surface 201 ofthe second layer 200 or the second major surface 102 of the first layer100 such that a total of about 15 g to about 30 g of adhesive 50 existsin the acoustic ceiling panel 25. In some embodiments of the presentinvention, the adhesive 50 is applied to at least one of the first majorsurface 201 of the second layer 200 or the second major surface 102 ofthe first layer 100 such that a total of about 20 g is applied.

As demonstrated by the non-limiting embodiments of FIGS. 7 and 8, thefirst adhesive strip 130, the second adhesive strip 131, the thirdadhesive strip 132, and the fourth adhesive strip 133 may each be acontinuous strip of adhesive that collectively define and form aclosed-geometry that circumscribes the central region 106 of the secondmajor surface 102 of the first layer 100.

As demonstrated by the non-limited embodiment of FIG. 9, the firstadhesive strip 130, the second adhesive strip 131, the third adhesivestrip 132, and the fourth adhesive strip 133 may each be a continuousstrip of adhesive, wherein the first adhesive strip 130, the secondadhesive strip 131, the third adhesive strip 132, and the fourthadhesive strip 133 of this embodiment are each discontinuous relative toone another.

As demonstrated by the non-limited embodiment of FIG. 10, the firstadhesive strip 130, the second adhesive strip 131, the third adhesivestrip 132, and the fourth adhesive strip 133 may each be intersecting,however, each of the first adhesive strip 130, the second adhesive strip131, the third adhesive strip 132, and the fourth adhesive strip 133 maybe a discontinuous strip of adhesive.

In one embodiment shown in shown in FIG. 7, the first adhesive strip 130may span a length that is equal to a length of the first upper edgeportion 120, the second adhesive strip 131 may span a length that isequal to a length of the second upper edge portion 121, the thirdadhesive strip 132 may span a length that is equal to a length of thethird upper edge portion 122, and the fourth adhesive strip 130 may spana length that is equal to a length of the fourth upper edge portion 123.In this embodiment, the first adhesive strip 130 and third adhesivestrip 132 overlap, the third adhesive strip 132 and the second adhesivestrip 131 overlap, the second adhesive strip 131 and the fourth adhesivestrip 133 overlap, and the fourth adhesive strip 133 and the firstadhesive strip 130 overlap.

In one embodiment shown in shown in FIG. 8, the first adhesive strip 130may span a length that is less than the length of the first upper edgeportion 120, the second adhesive strip 131 may span a length that lessthan the length of the second upper edge portion 121, the third adhesivestrip 132 may span a length that less than the length of the third upperedge portion 122, and the fourth adhesive strip 130 may span a lengththat is less than the length of the fourth upper edge portion 123. Inthis embodiment, each of the first adhesive strips 130, the secondadhesive strip 131, the third adhesive strip 132, and the fourthadhesive strip 133 are contacting to form a closed-geometry.

Adhesive 50 may be applied to the first major surface 201 of the secondlayer using the same process, wherein the central region 106 of thefirst layer corresponds to the central region 206 of the second layer200; the dotted boundary 170 of the first layer corresponds to a dottedboundary 270 of the second layer 270; the first, second, third, andfourth lower edge portions 220, 221, 222, and 223 of the second layer200 correspond to the first, second, third, and fourth upper edgeportions 120, 121, 122, and 123 of the first layer 100; and the first,second, third and fourth adhesive strips 130, 131, 132, and 133 may beapplied adjacent to the corresponding first, second, third, and fourthlower edge portions 220, 221, 222, and 223 of the second layer 200.

In some embodiments of the present invention, the acoustic ceilingpanels 20 of the present invention may be formed using a continuousprocess that includes passing the first layer 100 down a conveyor alonga machine direction, wherein the second major surface 102 of the firstlayer 100 is exposed facing upward. As the first layer 100 passes alongthe machine direction, the second major surface 102 passes underneath afirst glue unit which simultaneously applies the first adhesive strip130 and the second adhesive strip 131 (not pictured). The first layer100 can then turned 90 degrees and passed along the machine directionunder a second glue unit that simultaneously applies the third adhesivestrip 132 and the fourth adhesive strip 133 (not pictured). Thecontinuous process is also suitable for applying the first adhesivestrip 130, the second adhesive strip 131, the third adhesive strip 132,and the fourth adhesive strip 133 to the first face 201 of the secondlayer 200.

After application of the first adhesive strip 130, the second adhesivestrip 131, the third adhesive strip 132, and the fourth adhesive strip133 to at least one of the second major surface 102 of the first layer100 and the first major surface 201 of the second layer 200, the secondmajor surface 102 of the first layer 100 is joined to the first majorsurface 201 of the second layer 100.

Pressure may be applied to at least one of the second major surface 202of the second layer 200 or the first major surface 101 of the firstlayer to aid in the adhesive bonding between the first and second layers100. Heat may also be applied to the first layer 100 and the secondlayer 200 to ensure proper adhesive bonding between the first layer 100and the second layer 200. Optionally, a scrim 300 may later be appliedto the first major surface 101 of the first layer 100.

In non-limiting embodiments, the ceiling panel 20 may be a circle, oval,or polygon—e.g., rectangular (including square and non-square shapes) ortriangular. According to these embodiments the first layer 100 and thesecond layer 200 share the shape of the overall ceiling panel 20. Insome embodiments, the polygonal ceiling panels 20 may have rounded orsharp corners.

According to some embodiments, the ceiling panel 20 is substantiallyrectangular—the term “substantially rectangular” means a shape havingfour edges and four corners. Each corner forms angle ranging from 88 to92 degrees—alternatively about a 90 degrees. The four edges are eitherthe same length (square) or have a first pair of edges that are parallelto each other and extend a first length and a second pair of edges thatare parallel to each other and extend a second length, wherein the firstand second lengths are not equal (non-square). In some embodiments, thefirst pair of edges comprise the first upper edge portion 120 and thesecond upper edge portion 121, and the second pair of edges comprise thethird upper edge portion 122 and the fourth upper edge portion 123.

In some embodiments, the ceiling panel 20 is rectangular, wherein thefirst pair of edges and second pair of edges each have a length of 2feet. In some embodiments, the ceiling panel 20 has an overall thicknessranging from about 1.25 inches to about 2 inches—alternatively about1.75 inches.

The acoustic ceiling panel of the present invention exhibits certainacoustical performance properties. Specifically, the American Societyfor Testing and Materials (ASTM) has developed test method E1414 tostandardize the measurement of airborne sound attenuation between roomenvironments 3 sharing a common plenary space 2. The rating derived fromthis measurement standard is known as the Ceiling Attenuation Class(CAC). Ceiling materials and systems having higher CAC values have agreater ability to reduce sound transmission through the plenary space2—i.e. sound attenuation function.

Another important characteristic for the acoustic ceiling panelmaterials is the ability to reduce the amount of reflected sound in aroom. One measurement of this ability is the Noise Reduction Coefficient(NRC) rating as described in ASTM test method C423. This rating is theaverage of sound absorption coefficients at four ⅓ octave bands (250,500, 1000, and 2000 Hz), where, for example, a system having an NRC of0.90 has about 90% of the absorbing ability of an ideal absorber. Ahigher NRC value indicates that the material provides better soundabsorption and reduced sound reflection—sound absorption function.

Previous attempts to design acoustic ceiling panel shaving increased CACvalues (i.e., desirable reduction of sound transmission through theplenary space 2), has been tied with a simultaneous decrease in soundabsorption (NRC), which causes an increased amount of sound reflectedwithin a given room environment 3. It has been discovered that by usingthe acoustic ceiling panel 20 of the present disclosure, an increase inCAC performance can be achieved without substantial loss in NRCperformance.

Specifically, by coupling together the first layer 100 and the secondlayer 200 using adhesive 50 that is only applied to at least one of theperimeter regions 105, 205 of the first layer 100 or the second layer200, while also keeping the central regions 106, 206 of the first layer100 and the second layer substantially free of adhesive 50, it has beendiscovered that the resulting acoustic ceiling panel 20 will demonstratea marked improvement in CAC performance while avoiding substantialdetrimental change in NRC performance. According to the presentdisclosure, an insubstantial change in NRC performance is a loss of NRCvalue of less than or equal to (≦) 0.05.

Specifically, the acoustic ceiling panel 20 of the present disclosurehas a CAC value of 35 or greater, preferably 40 or greater, and has anNRC value of 0.7 or greater, preferably 0.9 or greater. The first layer100 may have an NRC value of at least 0.80, alternatively of at least0.90. The second layer 100 may have an NRC value of at least 0.65, and aCAC value of at least 35.

In some embodiments, the acoustic ceiling panel 20 of the presentdisclosure is formed by using a second layer 200 that has a CAC valuethat is greater than a CAC value of the first layer 100. The secondlayer 200 may also have an NRC value that is less than the NRC value ofthe first layer 200. The first layer 100 may be a noise absorption layerthat provides sound dampening within a single room environment 3. Thesecond layer 200 may be a noise blocking layer that providessoundproofing between adjacent room environments 3 that share the sameplenary space 2.

According to the present invention, once the acoustic ceiling panel 20has been properly installed into ceiling grid 5 of the ceiling system 1,the second major surface 202 of the second layer 200 faces the plenaryspace 2 of the ceiling system 1.

The invention will be described in greater detail by way of specificexamples. The following examples are offered for illustrative purposesand are not intended to limit the invention in any manner.

EXAMPLES

The Examples were prepared using a first layer comprised of fiberglasshaving the dimensions of 24 inches×24 inches×1 inch. The Examples wereprepared using a second layer comprised of mineral wool having thedimensions of 24 inches×24 inches×0.75 inches. The first and secondlayers have the following acoustical properties:

Fiberglass First Layer Mineral Wool Second Layer NRC Value 0.95 NRCValue 0.70 CAC Value N/A CAC Value 40

For the purpose of this disclosure, each of the individual fiberglassceiling panels has the same starting acoustical performance. For thepurpose of this disclosure, each of the individual mineral wool soundattenuation layers has the same starting acoustical performance.

Examples 1 and 2 were prepared by adhering together the first and secondlayers using polyvinyl acetate as the adhesive. The adhesive was appliedwithin the perimeter region of the first layer as first, second, third,and fourth continuous adhesive strips. Each of the adhesive strips wereadjacent to the corresponding first, second, third, and fourth upperedges of the first layer by an offset distance of ⅜ inches. Eachadhesive strip was applied with a width of ⅜ of an inch. Examples 1 and2 each used a total of 20 g of adhesive. The central region of Examples1 and 2 were substantially free of adhesive. Each of the central regionsof the first and second layers each have the dimensions of about 22.5inches×22.5 inches (506.25 sq. inches), making up about 88% of thesurface area of each of the second major surface of the first layer andthe first major surface of the second layer. The final thickness of theoverall acoustic ceiling panel is set forth in the table below.

Comparative Example 1 was prepared by evenly applying eight parallellines of polyvinyl acetate adhesive across the first major surface ofthe first layer—i.e. through the central region of the first layer.Comparative Example 1 used a total of 20 g of adhesive. ComparativeExamples 2 and 3 were prepared by applying sixteen checker board linesacross the first major surface of the first layer—i.e. through thecentral region of the first layer. Comparative Examples 2 and 3 each usea total of 20 g of adhesive. The final thickness of the comparativeacoustic ceiling panels are set forth in the table below.

TABLE 1 ΔNRC to Gauge Comp. (inches) Glued NRC Example 1 CAC Example 11.75 Perimeter (20 g) 0.95 0.05 43 (Insubstantial) Example 2 1.75Perimeter (20 g) 0.95 0.05 43 (Insubstantial) Comparative 1.76 8parallel Lines 1.00 — 40 Example 1 (20 g) Comparative 1.77 16 checkpattern 1.00 — 40 Example 2 lines (40 g) Comparative 1.78 16 checkpattern 1.00 — 39 Example 3 lines (40 g)

As demonstrated by Table 1, applying adhesive according to the presentdisclosure results in a marked improvement in CAC performance with onlyan insubstantial drop of five one-hundredths in NRC value. Thus,applying the adhesive according to the present disclosure allows forimproved in CAC performance without the substantial detrimentallyaffects the NRC performance.

Furthermore, applying adhesive according to the present disclosureinvention surprisingly resulted in improved CAC performance with anoverall ceiling panel thickness. CAC performance is a measure ofsoundproofing between adjacent room environments—typically, it isexpected that as thickness of the barrier between adjacent roomenvironments decreases, so does CAC performance. Thus, applying theadhesive according to the present disclosure allows for improved CACperformance while decreasing the volume required for such ceiling panel.

As those skilled in the art will appreciate, numerous changes andmodifications may be made to the embodiments described herein, withoutdeparting from the spirit of the invention. It is intended that all suchvariations fall within the scope of the invention.

The invention claimed is:
 1. An acoustic ceiling panel comprising: afirst layer comprising a first major surface and a second major surface,the second major surface of the first layer defined by a perimeter, thesecond major surface of the first layer comprising a perimeter regionadjacent the perimeter of the second major surface of the first layerand a central region circumscribed by the perimeter region of the secondmajor surface of the first layer; a second layer comprising a firstmajor surface and a second major surface, the first major surface of thesecond layer defined by a perimeter, the first major surface of thesecond layer comprising a perimeter region adjacent the perimeter of thefirst major surface of the second layer and a central regioncircumscribed by the perimeter region of the first major surface of thesecond layer; and the perimeter region of the second major surface ofthe first layer coupled to the perimeter region of the first majorsurface by an adhesive, each of the central region of the second majorsurface of the first layer and the central region of the first majorsurface of the second layer being free of adhesive and the centralregion of the second major surface of the first layer is in contact withthe central region of the first major surface of the second layer, toform a cohesive multilayer panel.
 2. The acoustic ceiling panelaccording to claim 1 wherein the acoustic ceiling panel has a CAC valueof 35 or greater.
 3. The acoustic ceiling panel according to claim 1wherein the acoustic ceiling panel has an NRC value of 0.7 or greater.4. The acoustic ceiling panel according to claim 1, wherein the adhesiveis applied to a limited section of the perimeter region.
 5. The acousticceiling panel according to claim 1, wherein the ceiling panel issubstantially rectangular in shape and the adhesive is applied to fourcorners of the perimeter region.
 6. The acoustic ceiling panel accordingto claim 1, wherein the second layer has a CAC value that is greaterthan a CAC value of the first layer, and the first layer has an NRCvalue that is greater than an NRC layer of the second layer.
 7. Theacoustic ceiling panel according to claim 6, wherein the second layerhas a CAC value of at least 35, and the first layer has an NRC value ofat least 0.7.
 8. A suspended ceiling system comprising: a ceiling gridcomprising a plurality of first members and a plurality of secondmembers, the first and second members intersecting one another to definea plurality of grid openings; a plenary space above the ceiling grid; aroom environment below the ceiling grid; and for each of the gridopenings, the acoustical ceiling panel according to claim 1 mounted tothe ceiling grid and positioned within the grid opening.
 9. The ceilingpanel according to claim 1, wherein the central region of the secondmajor surface of the first layer occupies at least 95% of the secondmajor surface of the first layer.
 10. The acoustic ceiling panelaccording to claim 1, further comprising: the first layer comprising aside surface extending between the first and second major surfaces ofthe first layer, the side surface of the first layer intersecting thesecond major surface of the first layer to form an upper edge of thefirst layer, the upper edge of the first layer forming the perimeter ofthe second major surface of the first layer; the second layer comprisinga side surface extending between the first and second major surfaces ofthe second layer, the side surface of the second layer intersecting thefirst major surface of the second layer to form a lower edge of thesecond layer, the lower edge of the second layer forming the perimeterof the first major surface of the second layer; the upper edge of thefirst layer comprising a first upper edge portion, a second upper edgeportion opposite the first upper edge portion, a third upper edgeportion extending between the first and second upper edge portions, anda fourth upper edge portion opposite the third upper edge portion andextending between the first and second upper edge portions; and theadhesive applied to the perimeter region of the second major surfacecomprising comprises a first adhesive strip extending adjacent to thefirst edge portion, a second adhesive strip extending adjacent to thesecond edge portion, a third adhesive strip extending adjacent to thethird edge portion, and a fourth adhesive strip extending adjacent tothe fourth edge portion.
 11. The ceiling panel according to claim 10wherein the first adhesive strip extends substantially parallel to thefirst edge portion, the second adhesive strip extends substantiallyparallel to the second edge portion, the third adhesive strip extendssubstantially parallel to the third edge portion, and the fourthadhesive strip extends substantially parallel to the fourth edgeportion.
 12. The ceiling panel according to claim 10, wherein the firstadhesive strip is spaced a first distance from the first upper edgeportion, the second adhesive strip is spaced a second distance from thesecond upper edge portion, the third adhesive strip extends is spaced athird distance from the third upper edge portion, and the fourthadhesive strip is spaced a fourth distance from the fourth upper edgeportion.
 13. The ceiling panel according to claim 10, wherein the first,second, third, and fourth adhesive strips collectively define aclosed-geometry circumscribing the central region.
 14. The ceiling panelaccording to claim 1, wherein the second major surface of the firstlayer is coupled to the first major surface of the second layer so thatthe perimeter of the second layer is aligned with the perimeter of thefirst layer.
 15. The ceiling panel according to claim 1, wherein thecentral region of the second major surface of the first layer occupiesabout 70% to about 99% of surface area of the second major surface ofthe first layer.
 16. The ceiling panel according claim 1, wherein theadhesive is polyvinyl acetate.
 17. The ceiling panel according to claim1, wherein the first layer is a sound absorption layer and the secondlayer is a sound blocking layer.
 18. The ceiling panel according toclaim 1, wherein the first layer is a fiberglass layer and the secondlayer is a mineral wool layer.
 19. The acoustic panel according to claim1, wherein the adhesive is applied in a continuous line or adiscontinuous line.
 20. An acoustic ceiling panel comprising: a firstlayer comprising a first major surface and a second major surface, thesecond major surface of the first layer defined by a perimeter, thesecond major surface of the first layer comprising a perimeter regionadjacent the perimeter of the second major surface of the first layerand a central region circumscribed by the perimeter region of the secondmajor surface of the first layer; a second layer comprising a firstmajor surface and a second major surface, the first major surface of thesecond layer defined by a perimeter, the first major surface of thesecond layer comprising a perimeter region adjacent the perimeter of thefirst major surface of the second layer and a central regioncircumscribed by the perimeter region of the first major surface of thesecond layer; and the perimeter region of the second major surface ofthe first layer coupled to the perimeter region of the first majorsurface of the second layer by a plurality of adhesive strips, theadhesive strips collectively forming a closed-geometry thatcircumscribes the central region of the second major surface of thefirst layer and the central region of the first major surface of thesecond layer.
 21. The ceiling panel according to claim 20, wherein theacoustic ceiling panel has a CAC value of 40 or greater.
 22. Theacoustic ceiling panel according to claim 20, wherein the acousticceiling panel has an NRC value of 0.90 or greater.
 23. The acousticceiling panel according to claim 20, wherein the second layer has a CACvalue that is greater than a CAC value of the first layer, and the firstlayer has an NRC value that is greater than an NRC layer of the secondlayer.
 24. The ceiling panel according to claim 20, wherein the centralregion of the second major surface of the first layer and the centralregion of the first major surface of the second layer are in freefloating contact with respect to one another.
 25. The acoustic ceilingpanel according to claim 20, further comprising: the first layercomprising a side surface extending between the first and second majorsurfaces of the first layer, the side surface of the first layerintersecting the second major surface of the first layer to form anupper edge of the first layer, the upper edge of the first layer formingthe perimeter of the second major surface of the first layer; the secondlayer comprising a side surface extending between the first and secondmajor surfaces of the second layer, the side surface of the second layerintersecting the first major surface of the second layer to form a loweredge of the second layer, the lower edge of the second layer forming theperimeter of the first major surface of the second layer; the upper edgeof the first layer comprising a first upper edge portion, a second upperedge portion opposite the first upper edge portion, a third upper edgeportion extending between the first and second upper edge portions, anda fourth upper edge portion opposite the third upper edge portion andextending between the first and second upper edge portions; and theplurality of adhesive strips comprising a first adhesive strip extendingadjacent to the first edge portion, a second adhesive strip extendingadjacent to the second edge portion, a third adhesive strip extendingadjacent to the third edge portion, and a fourth adhesive stripextending adjacent to the fourth edge portion.
 26. The ceiling panelaccording to claim 25 wherein the first adhesive strip is spaced a firstdistance from the first edge portion, the second adhesive strip isspaced a second distance the second edge portion, the third adhesivestrip extends is spaced a third distance from the third edge portion,and the fourth adhesive strip is spaced a fourth distance from thefourth edge portion.
 27. The ceiling panel according to claim 25,wherein the central region of the second major surface of the firstlayer occupies at least 95% of the second major surface of the firstlayer.
 28. The ceiling panel according to claim 25, wherein the firstlayer is a fiberglass layer and the second layer is a mineral woollayer.
 29. An acoustic ceiling panel comprising: a first layercomprising fiberglass and having a first major surface and a secondmajor surface, the second major surface of the first layer defined by aperimeter, the second major surface of the first layer comprising aperimeter region adjacent the perimeter of the second major surface ofthe first layer and a central region circumscribed by the perimeterregion of the second major surface of the first layer; a second layercomprising mineral wool and having a first major surface and a secondmajor surface, the first major surface of the second layer defined by aperimeter, the first major surface of the second layer comprising aperimeter region adjacent the perimeter of the first major surface ofthe second layer and a central region circumscribed by the perimeterregion of the first major surface of the second layer; and the perimeterregion of the second major surface of the first layer coupled to theperimeter region of the first major surface by an adhesive, each of thecentral region of the second major surface of the first layer and thecentral region of the first major surface of the second layer being freeof adhesive, to form a cohesive multilayer panel.